Lexus expands the LS 460 lineup for 2009 with the addition of all-wheel-drive versions of the LS 460 base sedan and the LS 460 L long-wheelbase sedan. The all-wheel-drive system in both sedans has a compact Torsen limited-slip differential, which distributes drive torque between the front and rear wheels. The system defaults torque 30/70 front to back under normal driving conditions to provide the feel of a rear-wheel-drive car, but shifts to 50/50 when road conditions require optimal traction or when the driver manually changes the configuration. Both AWD trims also come equipped with variable gear-ratio steering and a computer-controlled adaptive variable air suspension, which continually adjusts the shock absorbers to provide an optimal ride. In addition, Lexus adds front passenger seat memory as a standard feature for 2009. U.S. News and World Report ranks the LS sedan number one in the super-luxury car segment (which consists of cars priced over $60,000) due to its high level of reliability, plush interior, high-tech amenities, and smooth, quiet ride. However, some reviewers find the suspension a bit too soft and acceleration a tad too sedate, although no one calls the LS 460 underpowered. In fact, the LS 460's powerful 4.6-liter V8 engine produces an impressive 357 hp, which should be plenty for even the most pedal-heavy drivers. The V8 engine features dual continuously Variable Valve Timing with Intelligence (VVT-i), which increases torque at lower speeds and horsepower at higher speeds to improve performance, ensure good fuel economy, and reduce emissions. The emissions are so low that the LS 460 has received certification as an ultra-low emission (ULEV II) vehicle, which means it meets strict standards for hydrocarbon and nitrogen oxide emissions. Now in its fourth generation, the LS 460 serves as Lexus's flagship vehicle, showcasing elegant styling, luxury features, and cutting-edge technology. For instance, the LS 460's V8 engines link to the world's first eight-speed electronically controlled automatic transmission. All of the LS 460 trims, including the base rear-wheel-drive sedan, the AWD sedan, the rear-wheel-drive L long-wheelbase, and the L AWD, seat five passengers in a comfortable and luxurious cabin. Occupants are pampered by such upscale features as leather seats, wood and leather interior trim, a wood-and-leather-trimmed steering wheel and shift knob, a 16-way power-adjustable driver's seat and 12-way power-adjustable passenger seat, and a power tilt-and-slide moonroof. A 10-speaker audio system with an automatic sound levelizer and an in-dash 6-CD changer also comes standard. Options include heated and climate-comfort front and rear seats, a backup camera with a full-color display, electronic parking assist, a voice-activated DVD navigation system, and a 450-watt, 14-speaker Mark Levinson surround-sound audio system with a 6-CD/DVD auto-changer. Standard safety features include kneebag and side-curtain airbags, as well as traction control, electronic stability control, and four-sensor antilock brakes with brake assist and electronic brakeforce distribution, which adjusts the amount of fluid pressure on brakes to improve control during braking. The LS 460 also comes equipped with Lexus's Vehicle Dynamics Integrated Management (VDIM) system, which integrates braking, steering, stability control, and traction control to minimize the loss of traction in turns.